The present invention relates to a skin-whitening composition for external use containing bearberry extract and a reducing agent and to a method of whitening skin by topically applying a composition containing an effective amount of bearberry extract and a reducing agent.
Skin color is primarily determined by the amount of melanin present in the skin. Thus, in recent years, cosmetic compositions have been developed to reduce the amount of melanin in the skin and therefore, whiten the skin. These development efforts have focused on whitening agents that inhibit the function and activity of tyrosinase, which plays an important role in the biosynthesis of melanin. For example, it has been proposed to incorporate into cosmetic compositions tyrosinase activity inhibitors such as hydroquinone, vitamin C and its derivatives, kojic acid, arbutin, glutathione, cysteine, and mulberry extract, among others.
Despite the efficacy of the above compounds in producing whiter skin, alternatives that are more effective are continually being sought. It has now found that skin-whitening compositions that contain bearberry can be improved by adding a reducing agent such as a formaldehyde-donating compound to the composition. It is believed that the reducing agent reduces the tyrosinase, which surprisingly results in a dramatically increased efficacy in the whitening effect of the composition.
In addition, it is believed that the reducing agent may be able to alter the chemical composition of certain amino acids, of which several are key to the process of melanin production. As a result, increased skin whitening efficacy is obtained.